Over the air or radio communication systems are used in aircraft and air traffic control towers to provide directions to a pilot and to obtain requests and status information from the pilot. A problem arises, however, when an unexpected aircraft strays into a restricted area, and the local air traffic control tower does not know which radio communications channel the pilot is listening to or tuned in to. A goal here is to alert the pilot as soon as possible about the problem situation. One way to address this problem may be to define an additional channel that all aircraft systems are tuned into, simultaneously with another one of the pilot's choice, that has been adopted by all aircraft systems manufacturers and that is only to be used by an air traffic control tower wishing to immediately alert an approaching aircraft that is in the wrong airspace. In fact, there is an emergency frequency at 121.5 MHz used by aircraft, referred to as “guard” by military pilots. Most aircraft have two radios and military aircraft pilots monitor as a matter of policy this emergency frequency on their second radio while doing most or all of their normal communications on their primary radio. Civilian aircraft are also usually equipped with at least two radios; however, they rarely if ever monitor the 121.5 MHz channel with their second radio. It is a practice that has simply not taken hold in civilian pilot culture.